The brief includes delivering strategic, insight-led creative campaigns, as well as support on the "business as usual and sponsorship activity peaks".
Virgin Media provides broadband, TV, mobile phone and landline services across the UK and Ireland.
Tin Man’s first project for Virgin Media will be to support the rollout of its new all-in-one bundles, which combines Virgin Media’s broadband, mobile, TV and home phone for the first time.
"This is a big year for us and we’ve got exciting ambitions for the brand," chief corporate affairs officer Brigitte Trafford said.
"We were looking for a comms partner who was prepared to challenge us in the right way and share our vision for creative, strategic and impactful PR. We’re looking forward to creating some great work together."
Tin Man founder Mandy Sharp said: "We’ve long admired the Virgin Media brand and are beyond delighted that we get to do what we do best – deliver campaigns with heart, emotionally connecting audiences with the brand and reigniting the love. And hats off to the team for kicking off our relationship in true Virgin Media style by rocking up at Tin Man towers with a surprise bundle of congratulatory gifts – a first in my two-decade long career."